Hayo Terband is a spoken language teacher/researcher collaborating with linguists, speech-language pathologists, neurologists, audiologists, psychologists, and neurophysiologists. His research revolves around the developmental process of the speech production and perception system in both normal and disordered development, in which he combines behavioural experiments with neurocomputational modelling. Besides fundamental research, he also works on clinical applications and co-initiated the development and implementation of a process-oriented method for diagnostics and treatment planning of developmental speech disorders.

Terband, H. & Drullman, R. (2008). Study of an automated procedure for a Dutch sentence test for the measurement of the speech reception threshold in noise. Journal of the Acoustical Society of America, 124(5), 3225-3234.

Terband, H. (2013). Neurocognitive-Behavioral Research in Childhood Apraxia of Speech: where do we go from here? Paper presented at the CASANA Childhood Apraxia of Speech Research Symposium, Atlanta GA, February 21-22.

Terband, H., Rodd, J., & Maas, E. (2015). Simulations of feedforward and feedback control in apraxia of speech (AOS): Effects of noise masking on vowel production in the DIVA model. Proceedings of the 18th International Congress of Phonetic Sciences (ICPhS 2015), Glasgow, August 10-14.

Little is known about the neurological deficits and the linguistic processes that underlie the wide variety of symptoms that are found in developmental speech sound disorders. This forms a major bottleneck for diagnosis and treatment. The fundamental problem in isolating the underlying deficits is the developmental interaction between the different linguistic levels of processing. For example, poor articulation of particular speech sounds affects the patient’s perceptual acuity for contrasts involving these speech sounds. Individual patients vary widely in these developmental interaction patterns, and the effects of developmental interaction between linguistic levels on individual development is largely unknown.

In previous work, I used a modelling approach to address this problem. It was demonstrated that, by manipulating parameters independently and systematically, computational modelling studies can provide a unique insight into the relationship between core deficit, derived or consequential deficits, and adaptive strategies, and in how all of these express themselves in symptomatology. In particular, this pioneering work showed drastic differences in the linguistic level of a specific speech-motor impairment depending on the ability of the system for auditory self-monitoring, while the clinical expression remained largely the same. The current project expands these modelling studies to higher levels of the speech production process. Based on clinical theories, specific processing deficits will be implemented in the computational model, which will lead to specific predictions regarding a developmental trajectory. These predictions are then tested against speech data from speech production experiments involving children with the hypothesised diagnosis. The results will lead to a breakthrough in our understanding of the mechanisms involved in speech sound disorders. This knowledge is essential for focused and purposeful treatment for children that suffer from these disorders.

Project funded by NWO-VENI, awarded to Hayo Terband [Utrecht institute of Linguistics-OTS & University of Groningen].

Speech disorders are estimated to form about 75% of all communication disorders in children. The majority of these children are seen by speech therapists for diagnosis and treatment. A variety of methods of intervention has been developed, aimed at different parts of the speech production process. However, the diagnostic instruments that are currently available consist of tests that measure knowledge and skills. This results in a behavioural (=symptom) description, on which the clinician bases diagnostic classification, treatment program and referral to special education.

This project features the implementation of process-oriented diagnostics and treatment planning in clinical practice. Recent research into the mechanisms behind childhood speech disorders has yielded important insight into the relation between underlying deficits, compensatory adaptations and how these express themselves in symptomatology. The acquired knowledge comprises a wide range of methods for investigating speech production and perception, and the relation between production and perception, forming a solid theoretical basis for an approach based on diagnosing the processes involved in each individual case. This individualistic, process-oriented approach can be achieved through objective measurements of speech production in systematically varied speech tasks under systematically varied conditions and holds important advantages for the diagnosis and treatment of paediatric speech disorders.

Project funded by Revalidatiefonds, awarded to Ben Maasen [University of Groningen], Hayo Terband [Utrecht institute of Linguistics-OTS & University of Groningen] and Bert de Swart [Radboud University Nijmegen Medical Centre & HAN University of Applied Sciences].

3. Speech production in adults with intellectual disabilities: Assessment and intervention of dysfluencies and speech intelligibility.

In adults with intellectual disabilities (ID), communication is often troubled by disordered speech and/or impaired hearing. Miscommunication may cause diminished social skills, behavioral problems, and isolation. To improve quality of life, it is essential that adults with intellectual disabilities are able to make themselves understood.

The speech production of adults with ID is characterised in general by poor intelligibility and reduced fluency, however, little is known about the specific speech characteristics behind this. This study sets out to analyse and specify the types of dysfluencies and speech errors in a Dutch sample of adult persons with ID with a mixed aetiology. This type of inventarisation and classification has not yet been employed to speech data of people and is indispensable to determine the best possibilities for improving the fluency and intelligibility of speech production in this population.

Project funded by ZonMW (supportive part of the project “Prevention of communicative decline in adults with intellectual disabilities: assessment and intervention in disordered perceptive and productive functions.”), awarded to Ben Maassen [University of Groningen] and Ad Snik [Radboud University Nijmegen Medical Centre].

In collaboration with Marjolein Coppens [Radboud University Nijmegen Medical Centre].

Past projects

2005 – 2006 Development and validation of a method for the automated measurement of the speech reception threshold in noise. Internship at TNO Human Factors, Soesterberg. This work constituted the development of an automated/computerised sentence based hearing test, which has been used by TNO in signal processing research.

Publications

Terband, H. & Drullman, R. (2008). Study of an automated procedure for a Dutch sentence test for the measurement of the speech reception threshold in noise, Journal of the Acoustical Society of America, 124(5):3225-3234.

2006 – 2011 Tracing back the neurological deficits underlying Childhood Apraxia of Speech. PhD-project at Radboud University Nijmegen Medical Centre & University of Groningen. This project comprised neurocomputational modelling of Childhood Apraxia of Speech and to combine and quantitatively compare computer simulations and behavioural experiments.

2011 - 2012 Assessment of jaw stability in children with a variety of different developmental speech disorders. Research Associate at University of Groningen. Further elaboration/analysis of 3D kinematic data collected in a students’ project at Fontys University of Applied Sciences Eindhoven. This work investigated articulatory variability in the left-to-right (lateral) plane.